1. Field of the Invention
The invention under consideration relates to a method for operation of a compressor of a gas turbine, in which compressor air, which is inducted from the environment, is cooled by means of evaporative cooling before entry into the compressor.
During the operation of gas turbines, air which is inducted from the environment, is compressed in a compressor and fed to the gas turbine process. To increase the efficiency of the gas turbine it is known to additionally cool the inducted compressor air before entry into the compressor. This cooling takes place in many cases by injection of finest water droplets or water vapor into the air flow inducted by the compressor, which is cooled by the evaporation of the water.
The application of the evaporative cooling, however, can lead to temperature fluctuations in the inducted air flow, as a result of which the compressor is subjected to the risk of compressor surging. This compressor surging in serious cases can lead to destruction of plant components, and consequently, must be avoided in any event.
2. Brief Description of the Related Art
In known gas turbines, which operate with compressor induction air which is cooled by evaporative cooling, it is known to continually measure the temperature in the compressor induction air at different points during the operation. In this way, temperature fluctuations are identified, and in the event of a fluctuation amplitude being too high, the compressor can be shut down in the short term to avoid possible damage. For this purpose, corresponding maps are made available for each compressor, which indicate the limits of the temperature fluctuations which are specific to the compressor, above which a surging of the compressor can occur.
The temperature monitoring requires the use of a plurality of screened temperature sensors in the air induction pipe, and also associated hardware and software for the processing of the measurement signals. However, in these screened temperature sensors there is the problem that they frequently become wet in operation, and as a result of this, frequently provide erroneous measurements with temperature fluctuations which are ostensibly too high.
There remains a need, therefore, for a method for operation of a compressor of a gas turbine with compressor induction air which is cooled by means of evaporative cooling, which lessens the probability for erroneous warnings with a more reliable operation of the compressor, and which can be implemented cost effectively.